Usually a via structure in a multilayer printed circuit board (PCB) serves as a vertical transition between planar interconnected circuits based on planar transmission lines such as microstrip lines, striplines, coplanar lines and so on formed at different conductor layers of the PCB and are developed under the conditions providing low return and radiation (leakage) losses whole interconnect circuits used in electronic devices. These conditions stimulate the development different via structures such as blind vias, buried vias, shielded vias and so on.
To develop components and devices based on PCB technologies, in particular filters, resonant lengths of the planar transmission lines such as open- or short-circuited stubs are usually used. Variety of forms and dimensions of planar transmission line stubs be applied as building blocks gives a possibility to develop lowpass, highpass, bandstop and bandpass filters at different frequency bands. However, a planar structure of transmission line resonant stubs can lead to comparably large dimensions of filters as for an example at the frequency band up to 20 GHz. Also radiation (leakage) losses can be considerable in such discontinuities as planar transmission line stubs.